This invention relates to a carrier tape for slide fastener and has particular reference to a warp-knitted tape for mounting thereon a row of interlocking fastener elements.
There are known various types of warp-knitted tapes for use in the field of slide fasteners or zippers. Warp-knitted tapes of the known type are basically constructed with longitudinally extending chain stitches which form a multiplicity of wales and transversely extending lapping threads laid in to connect the wales coursewise. However, due primarily to their structural characteristics, the knitted tapes are susceptible to both longitudinal and transverse stretch and hence are not suitable per se for use in holding rows of fastener elements stably in position.
Attempts have been made to hold such stretch to a minimum mostly by making the knitted structure as fine and compact as possible. However, this has in turn led to the drawback that when sewing the fastener elements to the tape, the sewing needle tends to slip out of the correct line of path on account of resistance of too finely knitted threads, resulting in misaligned row of fastener elements on the tape. Such misalignment is pronounced in the event the tape is deficient in thickness at its edge to which the fastener elements are to be secured.